Wednesday, 24 April 2013

The problem of Viking silver ingots

During the Viking period, simple cast bar ingots had a number of different functions. They had an economic role, and were a convenient way of storing, transporting and exchanging silver within a bullion system. But they also served as a store of raw material for metalworking, and for the production of coins.

When ingots are found in hoards also containing deliberately fragmented silver and foreign coin, we can be reasonably confident that they passed as bullion. But what about ingots found as metal-detector finds, without an archaeological context?  In England, over 60 silver ingots of Viking-Age form have been recorded via metal-detecting, predominantly as isolated single finds. How can we be sure of their function?

An ingot with a rough and uneven appearance, from Yorkshire
(photo: Ian Cartwright)
One approach is to consider the form of the ingot. The majority of the single finds from England have parallel sides, rounded ends and D-shaped, oval or rectangular cross-sections. Fragmented ingots usually have clean cuts, made with a chisel. They thus have what could be described as a regular or consistent appearance (see ingot in lower picture). This is typical of ingots contained in hoards, where a standardised appearance may have helped to ensure confidence in the quality of the metal. 

However, this standardisation would not be needed for ingots used in metalworking. Indeed, some ingots associated with workshop areas on settlement sites in Scandinavia are uneven in appearance, with rough breaks. Such irregular ingots (such as the find from Yorkshire, above) were probably not used as a means of payment. That said, a regular shape does not preclude the use of an ingot in manufacturing.

A smooth, 'regular' ingot with rounded ends
and test marks (PAS 'Find-ID'
SF-144CA2, photo: PAS)
A second tactic to identify ingots as a means of payment is to consider evidence of ‘nicking’: the process designed to test the quality of the metal and/ or expose forgeries (see the ‘faking it’ blog below). Since a craftsperson would be unlikely to test the quality of an ingot s/he had recently cast, having already satisfied themselves of the quality of the silver going into the crucible, it seems unlikely that ingots used in metalworking or minting were regularly nicked. 

But nicking was a quick and easy means of testing the quality of silver in situations where the source of the silver was unknown, or where you might not trust your trading partner (such as at markets). It is therefore likely that nicked ingots acquired their test marks when they traded hands in commercial transactions. This is supported by the fact that nicking is widely observed on silver within Viking-Age hoards. In England, around half of all silver ingots found singly have test marks, a factor which points to their use as bullion. Notably, none of the 'irregular' ingots shows signs of testing, although the number of such ingots is small.

I can think of several other ways that ingots used in metalworking/ minting might be distinguished from those used as bullion.  Ingots used in commercial exchange might be expected to correspond to a particular weight unit, for instance, or to have a particularly high silver content. I’ll save these thoughts for a later blog article, but if anyone has any further suggestions in the meantime, please get in touch!